Tabatabaei et al International Journal Of Recycling of Organic Waste in Agriculture 2012, 1:2 http://www.ijrowa.com/content/1/1/2 ORIGINAL RESEARCH Open Access Compost' leachate recycling through land treatment and application of natural Zeolite Sayyed-Hassan Tabatabaei1*, Payam Najafi2, Sayyed Mohammad Javad Mirzaei3, Zohreh Nazem4, Manouchehr Heidarpour3, Shapoor Hajrasoliha4, Majid Afyuni5, Habiballah Beigi Harchegani6, Esmaeel Landi3, Leila Akasheh4, Mohammad Zamanian7, Mehdi Barani1 and Houssin Amini8 Abstract Background: The entrance of untreated wastewater or disposal leachate to water resources such as surface water, groundwater or irrigation water increases the risk of contaminant accumulation Removal or deduction of water contaminant concentration is then crucial before entering water to the natural resources or its transfusion directly to the soil as irrigation water Four studies were carried out in a pilot plant to evaluate the effect of natural zeolite to decrease chemical and biological index of compost factory leachate Land treatment was considered as the main strategy; however, some pounding and column experiment was implemented as well Wastewater chemical and biological indexes were analyzed These indexes consisted of Na, K, Mg, Ca, Co3, HCO3, Ni, Cd, Pb, Cr, chemical oxygen demand (COD), fecal coliform and total coliform (TC) In addition, soil was analyzed for EC, pH, cation and anion Results: In the first study, three types of zeolite derived from Semnan, Mashhad and Miyaneh mines were tested with four sizes (70, 140, 270 and 840 μm) at 25°C in summer 2007 It was concluded that high value of the cation concentration in the leachate causes neither adsorption of remaining cation nor heavy metals There was no statistically significant difference between the zeolite sizes and the heavy metal adsorption The results also showed that the adsorption ratios were 52%, 23% and 40% for Na, Ca and Mg, respectively In the second study, a loamy sand soil was enriched by adding 5% and 10% of the zeolite The result uncovered that adding 10% of the zeolite to the soil brings about more elements' absorption in comparison to application of the 5% zeolite Irrigation with the leachate reduced soil specific yield significantly In the third study, a complete randomized design experiment was used with six treatments (two kinds of soil, loamy sand and clay loam, and three levels of zeolite, 0%, 5% and 10%) and three replications performed in the lysimeter size The results revealed that irrigation with the leachate reduces soil bulk density, infiltration rate and saturated hydraulic conductivity Heavy metals could not be absorbed by loamy sand soil, whereas clay loam soil had a high ability to absorb heavy metals and reduce the salinity In loamy sand and clay loam soil, 10% zeolite had a significant effect on heavy metals' absorption The result of subsequent study (the same setup as the third study) exhibited the fact that the COD was significantly decreased by application of 5% zeolite, whilethis reduction occurred via applying 10% of zeolite in TC Conclusions: In short, this research indicated that the wastewater can be treated in a simple, economically process of land treatment through application of a clay loam soil texture with a cation pre-treatment Keywords: Zeolite, Heavy metal, Soil, Leachate, Wastewater, Compost * Correspondence: stabaei@agr.sku.ac.ir Department of Water Engineering, Faculty of Agriculture, Shahrekord University, Shahrekord, Iran Full list of author information is available at the end of the article © 2012 Tabatabaei et al.; licensee Springer This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited Tabatabaei et al International Journal Of Recycling of Organic Waste in Agriculture 2012, 1:2 http://www.ijrowa.com/content/1/1/2 Background Compost leachate is potentially a good source of soil fertility improvement However, high biological and chemical pollutions negatively influence this exploitation Heavy metals are considered as a major group of these potential contaminations To remove these pollutions, land treatment is a very cheap method, which is also suitable for leachate application in agriculture Because of leachate quality, land treatment application requires more investigation in order to identify the best leachate purification condition Municipal wastewater land treatment system that was started in the late 1880 s to early 1900s has been constantly modified over the time to address this phenomenon and to successfully operate as an effective treatment system (Robert 2004) Total land treatment systems in the USA were distinguished 304 units in 1940, and this number rose to 571 units in 1972 (U.S Environmental Protection Agency 1981) Land treatment was assumed as the most effective alternative solution in the USA from 1980 to 1905 and was applied by many communities along with sewage treatment (Robert 2004) In Melbourne, Austria, land filtration occurs in 3,833 of the farms annually and is able to treat an average of 30 Mm3 of sewage (about 60%) The land filtration system consists of the periodic application of wastewater on permeable soil and relies on purification by passage of leachate through the soil matrix for treatment purposes (Muneer and Lawerence 2004) Iran has very limited water resources and, at the same time, possesses very huge non-usage and abandoned lands A consolidate management system could support and utilize these unemployed lands for wastewater treatment Now, the question is whether the soil able to maintain heavy metals and square away nutrients to plants (Thawale et al 2006) Zeolites are hydrated aluminosilicates of the alkaline and alkaline earthmetals (Badillo-Almaraz et al 2003; Bell 2001; Kaya and Durukan 2004; Mumpoton 1999; Nazem 2007; Virta 1998) The framework of zeolite is open and contains channels and cavities where cations and water molecules are located The channel structure of zeolites is responsible for their function as a molecular sieve but is also important for ‘selective’ cation exchange The selectivity of different ions is determined by several factors such as the size and state of salvation of the ions, the charge (Si to Al ratio) and geometry of the framework, the number of cation sites available for occupation inside the framework and the temperature (Nazem 2007) Zeolites with dimension pores of to 10 Å are often called molecular sieves (IRNCID 1999) Clinoptilolite has the chemical formula of Na0.1 K8.57Ba0.04 (Al9.31Si26.83O72)19.56H2O (Erdem et al 2004; Mabel et al 2001) Exchangeable ions such as Na+1, K+1, Ca+2 and Mg+2are commonly occupied by clinoptilolite Page of (Ackley and Yang 1991) These cations are exchangeable with certain cations in solutions as well as lead, cadmium, zinc and manganese (Erdem et al 2004) Natural zeolites are good potential materials for water and wastewater treatment It is due to advantages of low-cost ion exchange and adsorption capability of natural zeolites In addition, it can be modified and regenerated (Widiastuti et al 2006) Natural zeolite has high CEC (100 meq/100 g) special clinoptilolite; therefore, the rate of both sorption and ion exchange are higher than any other natural zeolite (Kenderilik et al 2005; Teracy et al 1998) The selectivity of zeolite species, such as clinoptilolite and chabazite, for heavy metals based on the ionic radius and dissociation constant was as in the following order: Pb2+ > Ni2+ > Cu2+ > Cd2+ > Zn2+ > Cr3+ > Co2+ (Choi et al 2001; Ok et al 2007) Ion exchange of a specific cation is strongly influenced by the presence of competitive cations and complexion reagents such as anions (Inglezakis et al 2003a,b; Inglezakis et al 2005) The maximum sorption capacity of clinoptilolite toward Cd2+ was determined as 4.22 mg/g at an initial concentration of 80 mg/L and toward Pb2+, Cu2+ and Ni2+ as 27.7, 25.76 and 13.03 mg/g, respectively, at 800 mg/L The sorption results fitted well to the Langmuir and the Freundlich models The second one was better for adsorption modeling at high metal concentrations (Sprynsky et al 2006) Every day, almost 500 tons of garbage are processed in Isfahan Organic Fertilizer Factory (IOFF) and are transformed to compost This process produces about 40 cubic meters of leachate The objectives of these four studies then, were to investigate the power of the clinoptilolite to decrease chemical and biological index of the compost factory's leachate, while the focus of the study was on land treatment Methods First study The main objective of the first study was evaluation of the HM (Pb, Ni, Cd and Cr) and cation (Na, Ca and Mg) adsorption by a three Iranian natural zeolites (extracted from Miyaneh, Mashhad and Semnan) where Table shows the zeolite properties The statistical design was factorial with two levels, pounding time and zeolite size The first level had three pounding time values(70, 90 and 110 min), and the second one had four value sizes (70, 140, 270 and 840 μm) The experiment design was completely randomize with twelve treatments and three replications The 10 g of three Iranian natural zeolites was milled to pass a 0.5-mm stainless steel sieve for chemical analysis Then, these samples with 500 ml of leachate (Table 2) were placed in an orbital shaker (3,500 rpm) and were allowed to be equilibrated for three values of pounding times (70, 90 and 110 min) After this step, they were Tabatabaei et al International Journal Of Recycling of Organic Waste in Agriculture 2012, 1:2 http://www.ijrowa.com/content/1/1/2 Page of Table Zeolite chemical properties of three Iranian natural zeolites Zeolite SiO2 Al2O3 CaO K2O Na2O Fe2O3 MgO TiO2 MnO P2O5 LOI CEC Semnan 66.5 11.8 3.1 2.1 1.3 0.8 0.3 0.04 0.01 12 100 Miyaneh 65 12.2 2.3 1.8 1.5 0.1 0.03 0.04 0.01 12 110 Mashhad 68.04 10.14 0.97 1.15 4.31 2.04 1.03 0.31 0.01 0.04 1.94 150 These zeolites were extracted from Miyaneh, Mashhad and Semnan (Afrand Touska Company, Tehran, Iran in 2007) CEC, Cation exchange capacity; LOI, Loss of ignition Table Primary chemical analysis of input leachate SAR pH EC (dS/m) Cl− (meq/L) HCO3 (meq/L) Na+ (meq/L) Ca2+ (meq/L) Mg2+ (meq/L) TDS (mg/L) TSS (mg/L) Cr3+ (mg/L) Cd2+ (mg/L) Pb2+ (mg/L) Ni2+ (mg/L) 11.88 4.9 33.55 295 695 225 416 301 58400 9026 0.74 1.24 4.28 4.43 SAR, Sodium adsorption ratio; EC, Electrical conductivity; TDS, Total dry solid; TSS, Total suspended solid placed in the centrifuge for Thereafter, suspensions were centrifuged at 3,500 rpm for and the supernatant were filtered through Whatman no 42 filter paper (Whatman Ltd., India), and then sub-samples were digested by acid The parameters of analysis were measured in the solution before and after the contact with zeolite and calculated adsorption rate (AR) as well Results and discussion Tables and show that Na has desorbed from zeolite to solution samples This desorption was significant for Miyaneh and Mashhad samples (p = 0.01) and for Semnan zeolite case (p = 0.05), which could be due to zeolite structure The Ca and Mg with high concentration were absorbed by the zeolite significantly The results revealed that the pounding time was significant for the cation adsorption It could be seen that the maximum cation adsorption occurred in 110 for Miyaneh and Semnan cases, and 90 for Mashhad zeolite The results also indicated that the AR of Pb (p = 0.01), Cr and Ni (p = 0.05) was significant in Mashhad zeolite, whereas it was not significant for the two remaining zeolites In general, heavy metals' adsorption was too low in all zeolites It can be concluded that high value Table The mean of heavy metal removal percentage of leachate at three value of pounding time Zeolite Miyaneh Mashhad Semnan Second study This study was carried out in IOFF compost, Isfahan, Iran during the summer of 2007 The IOFF's soil and leachate were used for the experiment In general, soil could be classified as sandy-clay-loam in which the characteristics of soil and leachate are presented in Table The clinoptilolite was employed with a 0.279-mm diameter that was supplied from Semnan mine (center of Iran) The experiment was conducted in 20 columns Each column was made from PVC with a 110 and 400 mm diameter and height, respectively The first lower 50-mm Table The mean of heavy metal removal percentage of leachate at four value sizes Zeolite Size (μm) Miyaneh 840 −20.7 10.3 11 Na Ca Mg 270 −24 8.03 16 EC Pb Cd 13 8.6 7.11 1.8 1.8 5.5 8.2 0.33 Ni 8.2 10.1 Mg EC pH Pb Cd Ni Cr 140 −22.8 9.9 −1 1.01 −67 8.2 15 4.5 70 −19.6 10.9 22 0.66 0.96 14.4 9.92 9.3 −0.4 −0.33 6.4 Ca 10 r pH 0.93 0.19 10.3 4.08 28.4 Time (min) Na 70 concentration of the cations like Na, Cl and Mg might prevent the zeolite to absorb heavy metals As it is exhibited in Table 4, the results show that the zeolite size had no significant effect on heavy metals' adsorption; nonetheless, the 140- and 270-μm sizes had more AR Maximum heavy metal adsorption happened in 70, 110 and 70 to 90 (pounding time) for the cases of Miyaneh, Mashhad and Semnan zeolite, respectively 0.23 −0.06 10.4 7.01 9.2 −11 1.3 90 9.6 11.4 9.4 0.71 0.2 −8.9 13 6.8 4.4 840 −15.8 3.9 110 45.5 13.9 3.1 −2.2 −10 3.9 3.6 −9 270 −12.4 7.1 1.9 0.18 −0.15 11.9 17.1 15.1 21.1 1.5 17 140 −12.8 6.5 6.5 0.23 −0.3 8.05 12.3 11.6 24 70 −16 5.7 16.3 90 −18 2.3 31.7 −0.1 0.32 110 −6 70 14 29.9 7.5 −1 0.22 2.45 21 90 13 2.7 11.7 3.3 110 20 EC, Electrical conductivity 0.43 3.71 19 7.7 4.9 Mashhad 18 2.79 12.3 8.8 −3.4 1.31 0.25 17.5 6.4 23.6 32.1 70 −14 4.8 −0.8 0.1 −0.55 8.43 21.2 840 −14.5 11.9 26 270 −16.8 16.7 14 −0.8 0.33 0.25 3.36 24 9.6 8.6 140 −16.1 10 6.5 20.9 1.75 0.11 8.76 18 7.9 7.7 70 −16.1 12.5 10 Semnan 8.3 10.6 11.8 EC, Electrical conductivity; r, ratio 8 −1.5 0.18 2.53 14.8 7.3 24 8.8 7.2 23.8 4.7 16.8 21 −1.7 0.17 4.57 15.3 3.7 13.3 0.72 0.1 5.13 22.2 11.5 17.9 Tabatabaei et al International Journal Of Recycling of Organic Waste in Agriculture 2012, 1:2 http://www.ijrowa.com/content/1/1/2 Page of Table Soil chemical and physical characteristics and IOFF's compost leachate chemical properties Sample pH EC (dS/m) SAR OM % Ni (mg/L) Pb (mg/L) Cd (mg/L) Cr (mg/L) ρs (g/cm3) ρb (g/cm3) Soil 6.7 0.41 2.56 0.17 1.33 2.29 0.12 2.37 1.34 Leachate 4.9 33.5 11.9 - 4.44 4.28 1.24 0.73 - - EC, Electrical conductivity; SAR, Sodium adsorption ratio; OM, Organic matter; ρb, Specific gravity; ρs, Bulk density part of the column was filled with filtered sands Based on research treatment, the next 250 mm was filled with the soil as it is described below Again, the next 50 mm of the column was filled with filtered sand, and the remaining 50 mm was left empty for irrigation Then, leachate was used to irrigate the soil columns every days The total number of irrigation events and the depth of irrigation were 12 times and 20 mm, respectively A completely randomized block design was employed with four treatments and four replications Four treatments were implemented as the following: T1, sandy clay loam soil irrigated with fresh water (control); T2, sandy clay loam soil irrigated with leachate; T3, sandy clay loam soil mixed with 5% of the clinoptilolite irrigated with leachate; and T4, sandy clay loam soil mixed with 10% of the clinoptilolite irrigated with leachate Four columns were randomly selected for the soil initial condition measurement The rest of columns (16) were used for the analysis at the end of period Soil samples of the columns were analyzed in two different depths (0-10 cm and 10-25 cm) Drained water was collected from the columns, and soil analysis was conducted based on disturbed soil Results and discussion The results demonstrate that in soil column the salinity reduction (EC) value of drained water was decreased compare to the input value (Table 6) It illustrates that irrigation with the leachate has significantly increased the soil EC in all treatments (Table 7) It concludes that adding zeolite to the soil increases solution adsorption into the topsoil and prevents it to be leached towards subsoil In addition, the results show that irrigation with leachate increments soil OM percentage in all treatments (p = 0.01) The findings also explain that the maximum adsorbed concentrations of the Ca, Mg and Na were observed in T4 The findings furthermore highlight the fact that HCO3 was absorbed in topsoil (0-25 cm), while Cl was absorbed in the subsoil (25-40 cm) Again, a significant difference was observed between the treatments (p = 0.05) It can be seen also that the concentrations of the elements in drained water rose along with increasing number of irrigation events The results, likewise, reveal that adding zeolite to the soil neutralized the soil's pH Table presents that the Ca2+ concentration in drain water in T4 was lower than T3 and T2 (p = 0.05) Also, Ca concentration in drained waters increased with enhancing irrigation events It is noticeable that the high value cation concentration in the leachate has decreased the soil/clinoptilolite adsorption capacity Based on Table 6, the Mg concentration was lower than Ca concentration in drained water It means that soil and zeolite adsorbed Mg more than Ca in leachate treatments The Mg absorption from leachate was significantly different (p = 0.01) between the treatments based on Duncan test except at the end of period It indicated that high concentration of cations like Ca2+, Mg2+ and Na+ and anions such as Cl− and HCO3 in the leachate saturated the cation exchange capacity of related zeolite It shows that zeolite can accommodate a wide variety of cations (positive ions), such as Na+, K+, Ca2+, Mg2+, etc These positive ions are held rather loosely and can be readily exchanged with others in a contact solution (Mumpoton 1999) It can be concluded that irrigation with the leachate has decreased drain water's SAR in all treatments (Table 6) It has a significant difference (p = 0.05; based on the Duncan test) Briefly, in order to raise the sandy clay loam ability in this research, different levels of zeolite were blended with soil, and the capacity of heavy Table Chemical properties of output leachate Mean of total period T Sy (%) pH EC (dS/m) Ca (meq/L) Mg (meq/L) 33.45 7.3 7.73 6.63 34 6.6 27.37 212.3 148.7 30 6.38 26.82 213.2 130.4 25.75 6.17 26.32 201.2 104 HCO3 (meq/L) Cl (meq/L) Ni (mg/L) Pb (mg/L) Cd (mg/L) Cr (mg/L) SAR 7.12 30.17 20.42 0 0 2.86 148.1 463.97 198.8 1.75 1.35 0.11 10.78 148.3 432.97 188.1 1.71 1.35 0.12 10.94 147 374.31 176 1.52 1.25 0.1 10.43 Na (meq/L) T, Treatment; Sy, Specific yield; EC, Electrical conductivity; SAR, Sodium adsorption ratio Tabatabaei et al International Journal Of Recycling of Organic Waste in Agriculture 2012, 1:2 http://www.ijrowa.com/content/1/1/2 Page of Table Chemical and physical properties of soil treatments at the beginning and end of experiment Cl Ni Pb Cd (mg/L) Cr OM (%) SP Lime SAR ρb ρs (g/cm3) 24 30 1.25 2.9 0.1 0.22 22.9 69 2.4 1.1 2.3 2.18 15 30 1.12 2.5 0.1 0.17 33.2 70 2.3 1.3 2.4 2.84 20 30 1.57 2.4 0.1 0.15 22.4 60 1.4 2.5 0.5 2.18 30 10 1.2 2.3 0.1 0.24 23.7 59 2.2 1.3 2.3 0.4 2.18 20 30 1.65 2.6 0.1 0.19 21.7 68 2.3 1.3 2.5 1.4 0.4 2.18 20 20 1.55 1.8 0.1 0.17 21.5 68 2.3 1.4 2.3 1.4 0.5 2.84 25 30 1.6 0.1 0.1 23.1 58 1.5 2.2 0.38 1.4 0.4 2.84 30 10 1.67 1.8 0.1 0.14 23.5 58 1.4 2.4 0.79 7.7 18.7 20.1 10 33.3 1.85 2.7 0.1 0.4 0.24 23.1 46 5.5 1.2 2.3 7.9 9.87 8.4 149 86.9 50 76.7 1.71 2.5 0.2 0.4 1.56 22.1 46.3 9.8 1.2 2.3 8.1 13.6 9.7 177 97.6 50 117 1.73 2.9 0.1 0.3 1.29 25.8 46.3 10 1.5 2.6 7.9 14.9 27 156.7 97.6 63 143 1.46 2.9 0.1 0.2 1.71 24.4 46.6 11.4 1.3 2.3 7.6 0.78 6.4 18.73 19.6 13.3 50 1.25 2.7 0.1 0.4 0.25 22.3 46.7 5.6 1.3 2.3 8.3 16.8 11 144 86.9 23.3 86.7 1.72 2.7 0.1 0.3 0.96 24 47.3 5.9 1.5 2.3 8.4 13.9 11 117.1 97.6 33.3 127 1.63 2.5 0.1 0.2 1.06 22.2 49 10 1.4 2.2 8.05 11.5 20.4 112.4 86.9 30 170 1.43 2.3 0.1 0.2 1.44 25.1 48 10.7 1.3 2.3 Time Depth (cm) T pH EC (dS/m) Ca Mg Before 0–10 6.6 0.41 1.4 0.4 2.84 7.1 0.25 1.4 0.4 6.9 0.37 1.4 0.4 6.5 0.28 1.4 6.8 0.38 1.4 0.31 6.6 0.36 6.5 7.8 10–25 After 0–10 10–25 Na HCO3 (meq/L) T, Treatment; EC, Electrical conductivity; OM, Organic matter; SP, Saturation percentage; SAR, Sodium adsorption ratio; ρb , Specific gravity; ρs, Bulk density metals' absorption in the soil was estimated According to the results of this research, high concentration of cations in the leachate filled the cation exchange capacity of the zeolite Therefore, heavy metals such as Ni, Pb, Cd and Cr were all absorbed by the soil with suitable values; however, soil enrichment using certain percentages of this research (5% and 10%) could not significantly enlarge adsorption capacity Third study The main objective of this study was to investigate the possibility of leachate remediation by land and the effects of leachate application on some specified soil physical properties Hence, a complete randomized block design experiment with six treatments was applied (A0, loamy sand soil (Table 8); A5, loamy sand soil mixed with 5% zeolite; A10; loamy sand soil mixed with 10% zeolite; B, clay loam soil (50% Organic Fertilizer Factory mixed with 50% Khaton-Abad farm); B5, clay loam soil mixed with 5% zeolite; and B10, clay loam soil mixed with 10% zeolite), and three replications were performed in 18 PVC soil columns filled with treatment soils (60-cm diameter and 100-cm height) Clinoptilolite zeolite was mainly Table Chemical properties of two kinds of soils used in experimental studies OC (%) pH EC(ds/m) Texture 0.1 6.85 0.34 Loamy sand 0.48 6.54 0.38 Clay loam EC, Electrical conductivity; OC, Organic carbon taken from Semnan City For irrigation of columns, the leachate extracted from Isfahan Organic Fertilizer Factory compost was utilized During the research period, the soil columns were irrigated 16 times on a weekly basis The water added to the soil columns was cm each time Results and discussion The results showed that adding zeolite to the treatments increased the bulk density against irrigation, while the leachate caused reduction of the bulk density After irrigation with leachate, high concentration of Na+ dispersed the soil; nevertheless, it was not significant in all treatments Adding zeolite to loamy sand and clay loam soils reduced infiltration and saturated hydraulic conductivity It sounds that the particles of zeolite lied between pores of the soil As a result, heavy metals such as Ni, Pb, Cd and Cr could not be absorbed by loamy sand soil (Figure 1) and the EC was not significant (p = 0.01) in this soil, whereas clay loam soil had a high ability to absorb heavy metals and reduce the salinity In loamy sand soil, zeolite (10%) had a significant aptitude in absorption of heavy metals and reduction of salinity; nevertheless, in clay loam soil, zeolite did not have any positive effect on the soil Fourth study The setup of this study was the same as the third study Some chemical pollution indexes such as Na, Ca, Mg, chemical oxygen demand (COD), fecal coliform and Tabatabaei et al International Journal Of Recycling of Organic Waste in Agriculture 2012, 1:2 http://www.ijrowa.com/content/1/1/2 Cd (mg L-1) Ni (mg L-1) Cr (mg L-1) Pb (mg L-1) Page of Figure Concentration of absorbed heavy metals (mg/L) by loamy sand soil and clay loam soil total coliform (TC) were then analyzed at this step The treatments were similar to the third study Results and discussion Effects of soil texture and zeolite on chemical oxygen demand (COD) The leachate derived from the compost had a strong brown color, indicating that it is an organic material The mean value of COD was estimated equal to 100 g/L during the experimental period In addition, above mentioned leachate existed more in the clay loam soil than the loamy sand soil Because clay loam soil has higher CEC than other soils, it could absorb more OM from the leachate On the other hand, due to small pores of the clay loam, the air condition is poor Loamy sand soil mixed with 5% zeolite had better removal efficiency than clay loam soil mixed with zeolite The results showed that adding zeolite to the clay loam does not have any significant effect on COD Its looks depend to high-level adsorption of OM by this treatment Effect of soil texture and zeolite on total coliform (TC) Clay loam has higher elimination capacity than loamy sand soil because clay loam soil has lower permeability rate than the other one On one hand, total coliform was absorbed by the soil of the column and decomposed by nematode and protozoa On the other hand, specific surface of clay accelerate coliform adsorption from the leachate Sandy loam with zeolite had high significant impact on removal capacity of TC, but the clay loam was the opposite Effects of soil texture and zeolite on Na, Ca and Mg of the leachate Clay loam soil showed better performance on Na, Ca and Mg adsorption than the sandy loam soil The reason is that clay loam soil has higher CEC than the other one Soil and zeolite particles tend to adsorb these bivalent cations than Na, and a significant difference was recognized between their adsorptions by soil and zeolite particles (p = 0.05) Clay loam soil mixed with 10% zeolite has the highest cation elimination capacity than other treatments because this soil has most specific surface and CEC Conclusions According to the results of this research, following conclusions can be presented: First, study revealed that the AR in Mashhad zeolite was significant for Pb (p = 0.05) and Cr/Ni (p = 0.05) Nevertheless, it was not significant for the two remaining zeolites Zeolite size had no significant effect on the heavy metals' adsorption; however, the 140 and 270-μm size had more AR Maximum heavy metals' adsorption happened in 70, 110 and 70-90 (pounding time) for Miyaneh, Mashhad and Semnan zeolite, respectively Maximum cation adsorption occurred in 110 for Miyaneh and Semnan zeolite, and 90 for Mashhad zeolite Tabatabaei et al International Journal Of Recycling of Organic Waste in Agriculture 2012, 1:2 http://www.ijrowa.com/content/1/1/2 In the second study, high concentration of cations of the leachate filled the cation exchange capacity of the zeolite and soil, so heavy metals such as Ni, Pb, Cd and Cr were absorbed by the soil negligibly Notwithstanding, soil enrichment with 5% and 10% zeolite could not significantly enhance the adsorption capacity Additionally, the majority of heavy metals were absorbed in the topsoil (0-10 cm) High concentration of cations and anions in the leachate saturated soil CEC and also absorbed anions and cations by soil/zeolite Furthermore, adding 10% zeolite to the soil (T4) resulted in more absorption Heavy metals, Ca and Mg, were absorbed in topsoil, but Cl- was mainly absorbed in subsoil than the topsoil Na+, SAR, HCO3 and Cl− concentrations in drained water were increased with increased number of irrigation events In the third study, adding zeolite to the treatments enhanced the bulk density and reduced infiltration and saturated hydraulic conductivity, whereas irrigation with the leachate caused reduction of the bulk density Clay loam soil had a high ability in absorption of heavy metals and reduction of salinity Similarly, loamy sand soil mixed with 10% zeolite had a significant impact on absorption of heavy metals and reduction of salinity Eventually, in the fourth study, adding zeolite to clay loam had no significant effect on COD It sounds dependent to high-level adsorption of OM by this treatment Sandy loam with zeolite had high significant impact on removal capacity of TC Oppositely, clay loam had no impact on removal capacity of TC Clay loam implemented better performance than the sandy loam soil on Na, Ca and Mg adsorption The reason could be the fact that this soil had most specific surface and CEC Abbreviations EC: Electrical conductivity; OM: Organic matter; SAR: Sodium adsorption ratio; ρb: Specific gravity; ρs: Bulk density; T: Treatment; Sy: Specific yield; TDS: Total dry solid; TSS: Total suspended solid; CEC: Cation exchange capacity; LOI: Loss of ignition Competing interests The authors declared that they have no competing interest Acknowledgments Researchers would like to thank the officials of the University of Shahrekord, Islamic Azad University, Khorasgan Branch and Isfahan Compost Factory for their financial supports of this research project Authors’ contributions ZN, LA, SM, JM, and MZ collected the lab/experimental data S-HT, PN and MH carried out the supervision on the data analysis and revised them SH, MA, HBH and EL revised the thesis MB and HA helped in laboratory analysis All authors read and approved the final manuscript Author details Department of Water Engineering, Faculty of Agriculture, Shahrekord University, Shahrekord, Iran 2Department of Soil Science, Faculty of Agriculture, Khorasgan Branch, Islamic Azad University, Isfahan, Iran Department of Irrigation, Faculty of Agriculture, Isfahan University of Technology, Isfahan, Iran 4Department of Soil Science, Faculty of Agriculture, Islamic Azad University, Khorasgan Branch, Isfahan, Iran 5Department of Soil Page of Science, Faculty of Agriculture, Isfahan University of Technology, Isfahan, Iran Department of Soil Science, Faculty of Agriculture, Shahrekord University, Shahrekord, Iran 7Water Engineering, Faculty of Agriculture, Shahrekord University, Shahrekord, Iran 8Department of Soil Science, Faculty of Agriculture, Khorasgan Azad University, Isfahan, Iran Received: 29 March 2012 Accepted: August 2012 Published: August 2012 References Ackley MW, Yang RT (1991) Diffusion in ion exchange clinoptilolite AICHE J 37:1645 Badillo-Almaraz V, Trocellier P, Davila-Rangel I (2003) Nucl Instrum Methods Phys Res Sect B 210:424 Bell RG (2001) What are zeolites? BZA available on http://www.bza.org/zeolites html Choi CL, Lee DH, Kim JE, Park BY, Choi J (2001) Salt-thermal zeolization of fly ash Environ Sci Technol 35:2812–2816 Erdem E, Karapinar NA, Donat R (2004) The removal of heavy metal cations by natural zeolites Colloid and Interface Sci J 280:309–314 Inglezakis VJ, Loizidou MD, Grigoropoulou HP (2003a) Ion exchange of Pb2+, Cu2+, Fe3+ and Cr3+ on natural clinoptilolite: selectivity determination and influence of acidity on metal uptake Colloid Interface Sci J 261:49–54 Inglezakis VJ, Zorpas AA, Loizidou MD, Grigoropoulou HP (2003b) Simultaneous removal of metals Cu2+, Fe3+ and Cr3+ with anions SO42- and HPO42- using clinoptilolite Microporous Mesoporous Mater 61:167–172 Inglezakis VJ, Zorpas AA, Loizidou MD, Grigoropoulou HP (2005) The effect of competitive cations and anions on ion exchange of heavy metals Sep Purif Technol 46:202–207 IRNCID (1999) National Conference on irrigation and Proceeding of the 9th Iranian National Committee on Irrigation & Drainage p 37 IRNCID publication Tehran, Iran Kaya A, Durukan S (2004) Utilization of bentonite-embedded zeolite as clay liner Appl clay Sci 25:83–91 Kenderilik EM, Altan M, Yorukogullari E (2005) Our important source storing hydrogen: the natural zeolite Andolu University, Eskisehir, Turkey, Graduate School of Science Mabel VM, Raymundo LC, Ronald G, Blanca EJC, Pedro JJA (2001) Heavy metal removal with Mexican clinoptilolite: multi component ionic exchange Wat Res J 35(2):373–378 Mumpoton FA (1999) Uses of natural zeolites in agriculture and industry Proceeding of National academy of sciences USA 96(7):3463–3470 Muneer M, Lawerence R (2004) Phosphorus characteristics of soils treated with sewage effluent using land filtration at Werribee sewage treatment complex, Victoria In: SuperSoil 2004: 3rd Australian New Zealand Soils Conference University of Sydney, Australia, 5-9 December 2004 Nazem Z (2007) Effects of land treatment application for treated leachate of Isfahan Compost Factory Dissertation in Department of Soil Science, Agricultural Faculty, Islamic Azad University, Khorasgan Branch, Isfahan, Iran Ok YS, Yang JE, Zhang YZ, Kim SJ, Chung DY (2007) Heavy metal adsorption by a formulated zeolite-Portland cement mixture Hazardous Materials J 147:91–96 Robert KB (2004) Interpreting science in the real world for sustainable land application JEQ 34:174–183 Sprynsky M, Duszewski B, Terzyk AP, Namiesnik J (2006) Study of the selection mechanism of heavy metal (pb2+, cu2+, Ni2+, cd2+) Colloid and Interface Science 304:21–28 Teracy MMJ, Marcus BK, Bisher ME, Higgines JB (1998) Proceedings of the 12th International Zeolite Conference, vol Maryland, USA Thawale PR, Juwarkar AA, Singh SK (2006) Resource conservation through land treatment of municipal wastewater J Curr Sci India 90:704–710 U.S Environmental Protection Agency (1981) Process Design Manual for Land Treatment of Municipal Wastewater 77:008, EPA 625/1 General Books LLC, USA Virta RL (1997) Zeolites Geological Survey Publication, U.S Geological Survey, USA Available on: minerals.usgs.gov/minerals/pubs/commodity/zeolites/ zeomyb97.pdf Widiastuti N, Wu H, Ang M, Dong-ke Zhang (2006) The potential application of natural zeolite for greywater treatment The 34th Australasian Chemical and Process Engineering Conference, Auckland, New Zealand doi:10.1186/2251-7715-1-2 Cite this article as: Tabatabaei et al.: Compost' leachate recycling through land treatment and application of natural Zeolite International Journal Of Recycling of Organic Waste in Agriculture 2012 1:2